PORTLAND, Maine — Wildlife biologists are using extracted teeth from black bears to monitor Maine’s bear population and determine how best to manage it.

The Department of Inland Fisheries and Wildlife is asking bear hunters to give up a tooth from their harvested animals in the name of science. In the past two years, 2,032 hunters have answered the call.

Biologists can establish a bear’s age by cutting a cross-section of a tooth and counting the rings under a microscope, much the way a tree’s age can be determined by counting the rings on a cross-section of trunk, said biologist Jennifer Vashon.

By determining the ages of the bears that are killed during each year’s hunt, biologists can better estimate how many bears there are throughout the state and how old they are. This year’s hunt began Aug. 30 and continues through Nov. 27.

Story continues below advertisement.

“By having multiple years of that information, you can have a good ability to reconstruct the true population,” Vashon said.

The wildlife department every 15 years produces an assessment of the state’s black bear population that is used to develop a plan on how best to manage the population. The state’s current bear management program aims to stabilize the bear population to maintain hunting and viewing opportunities while limiting conflicts between bears and people.

At the time of the last assessment in 1999, biologists estimated Maine’s bear population at 23,000. It is now thought to be between 23,000 and 30,000, Vashon said.

Biologists for years have monitored the bear population by reviewing hunter data and using radio collars that have been placed on several dozen bears across Maine to gauge population densities in given areas.

The tooth-aging program is simply another management tool to help measure population trends, Vashon said.

Last year, about two-thirds of the teeth submitted by hunters came from bears that were 3 years old or younger, Vashon said. The oldest bear was a 25-year-old female, and the oldest male bear was 20 years old.

Younger bears have a higher mortality rate than older bears. They are more likely to cross roads and show up in people’s yards, and are more vulnerable to hunters, she said.

“They’re young and brash, don’t think of everything and lack experience,” she said.